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The Earth’s atmosphere today has changed, when compared with the Earth’s earliest atmosphere, (a) Two processes that caused changes were the cooling of the atmosphere and photosynthesis - Edexcel - GCSE Chemistry - Question 3 - 2015 - Paper 1
Question 3
The Earth’s atmosphere today has changed, when compared with the Earth’s earliest atmosphere, (a) Two processes that caused changes were the cooling of the atmosphe... show full transcript
Worked Solution & Example Answer:The Earth’s atmosphere today has changed, when compared with the Earth’s earliest atmosphere, (a) Two processes that caused changes were the cooling of the atmosphere and photosynthesis - Edexcel - GCSE Chemistry - Question 3 - 2015 - Paper 1
Step 1
State how cooling changed the composition of the Earth’s atmosphere.
Answer
Cooling of the atmosphere led to the condensation of water vapor. As the temperature dropped, water vapor began to condense, resulting in the formation of liquid water. This removed water vapor from the atmosphere, contributing to a decrease in its overall composition.
Step 2
Explain how photosynthesis changed the composition of the Earth’s atmosphere.
Answer
Photosynthesis significantly altered the Earth's atmosphere by reducing carbon dioxide levels as plants absorbed this gas to produce glucose and release oxygen. Over time, this process increased the levels of oxygen in the atmosphere, creating a more suitable environment for aerobic life.
Step 3
Step 4
Calculate the volume of air that passed over the copper.
Answer
To find the volume of air that passed over the copper, we start with the formula:
V = rac{21 imes 50}{100} = 10.5 ext{ cm}^3
After 50 minutes, the total volume of air passing over is calculated as:
Thus, the volume of air after this reaction is:
79 imes rac{50}{100} = 39.5 ext{ cm}^3.